Re: [PATCH v3 3/3] ASoC: rt715:add micmute led state control supports

[Mark Brown <broonie@kernel.org>]

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On Wed, Jan 13, 2021 at 01:18:14AM +0800, Perry Yuan wrote:

> Some new Dell system is going to support audio internal micphone
> privacy setting from hardware level with micmute led state changing
> When micmute hotkey pressed by user, soft mute will need to be enabled
> firstly in case of pop noise, and codec driver need to react to mic
> mute event to EC(embedded controller) notifying that SW mute is completed
> Then EC will do the hardware mute physically within the timeout reached

> This patch allow codec rt715 driver to ack EC when micmute key pressed
> through this micphone led control interface like hda_generic provided
> ACPI method defined in dell-privacy micmute led trigger will be called
> for notifying the EC that software mute has been completed

It feels like there's an abstraction problem here with this being hard
coded in a specific CODEC driver.

>  #include <linux/soundwire/sdw.h>
> @@ -244,6 +245,7 @@ static int rt715_sdca_get_volsw(struct snd_kcontrol *kcontrol,
>  	unsigned int max = mc->max;
>  	int val;
>  
> +	pr_err("++++++rt715_sdca_get_volsw++\n");
>  	val = snd_soc_component_read(component, mc->reg);
>  	if (val < 0)
>  		return -EINVAL;

This shouldn't be in the patch.

> @@ -287,6 +291,18 @@ static int rt715_sdca_put_volsw(struct snd_kcontrol *kcontrol,
>  			return err;
>  	}
>  
> +#if IS_ENABLED(CONFIG_DELL_PRIVACY)
> +	/* dell privacy LED trigger state changed by muted/unmute switch */
> +	if (mc->invert) {
> +		if (ucontrol->value.integer.value[0] || ucontrol->value.integer.value[1]) {
> +			rt715->micmute_led = LED_OFF;
> +		} else {
> +			rt715->micmute_led = LED_ON;
> +		}
> +		ledtrig_audio_set(LED_AUDIO_MICMUTE, rt715->micmute_led);
> +	}
> +#endif
> +

This doesn't look good.  There's nothing Dell specific here, and nothing
about this is conditional on any sort of runtime detection of Dell
systems, it's not obvious why this is conditional on DELL_PRIVACY or why
we only report the state if the control is inverted.

I'm also not convinced that it's a good idea to set the mute LED if only
one channel in a stereo microphone is muted, that seems likely to lead
to surprising behaviour for users.

TBH I don't understand why this isn't being done in generic code.

> +	bool micmute_led;

What is this for, it never seems to be read except for in the function
where it's set?

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